Apparatus for treating sewage



Jan. 14, 1936. F, SjCURRlE APPARATUS FOR TREATING SEWAGE Filed `Jan. 24,1954 Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE APPARATUS Foa'.raEATrNG sEwAGl-z Frank s. Currie, san Beniamino, application January24, 1934, serial No. 108,131. i .4 claims. (cram-s) U ments required ininstallation of thisnature; and, fourth, to accomplish these objects bymeans of simple construction. t

My objects are attained in the manner illustrated in the accompanyingdrawing, in' which- ]5 Figure v1 is a diagrammatic pla .stantiallycomplete activated sludge plant, which embodies my invention;

,A Figure 2 is a cross-sectional elevation of a portion of the aforesaidconstruction, taken on the plane -22 of-Figure l; and

,Figure 3 is a sectional plan Viewof a type of construction that may besubstituted for certain parts shown in the other two gures. l

Similar reference numerals refer to similar parts throughout the severalviews.

In the arrangement of plant illustrated in Figs. lI and 2, untreatedsewage enters -the plant through inlet pipev 5." It'then flowslongitudinally Vthrough a primary clarifying tank E, wherein 3Gsettlement of avery considerable portion of the solid contents takes'place. Under-flow weirs 1 assistin this process. The settled solids areco1- lected in a sump 8, and are removed therefrom',

more or less continuously, by a pump 9; being discharged by the pumpinto a sludge digester I.

The partly clarified sewage from primary clarier 6 flows (or is pumped)through pipe 2 into a series of 4aeration chambers, indicated at 3, I4,I5 and I6. .These chambers should be' arranged in such manner that theymay be operated singly or together; the usual arrangement being topassthe sewagek through all of them in'series.

' In Figs. 1 and 2, the aeration chambers are l .shown in the form ofannular sectors, disposed aboyt a common center. Each of them isprovided wit a vertical outlet. pipe |1, leadingv to a connecti giitting`l8, and thence to a vertical `pipe lsfserving as an inlet tosecondary clarifier 2l. A exible arrangement of inlet devices for theaeration chambers, such as the gates 22, also is provided.' This permitsof cleaning the chambers separately, and of meeting other possibleoperating contingencies.. .Each aeration chamber thus is capable oi'being operated asan independent' unit.

view of a sub# clarier 2| overflows circ ar eir 29, at the outertquartz. The compressed air from the conduits 3 arrows 36, 31, 38 and39. This circular motion,

Further settlement and separation of contained solids takes place insecondary clarifier 2|, the f solids tending to' settle in sump 23. Aportion of these solids may be more or less continuously pumpedtherefrom, by means of pipes v24 and 5 pump 25, to a Weir box 26 at arelatively high elevation. This Weir box overflows into re-aerationchamber 21, wherein re-vivification (activation) of the containedaerobic bacteria takes place. ber may be utilized for seeding theaeration chambers |3|6 in Athe usual manner, by the use of gates 22. Agutter 28 is, provided around the outer perimeter of the-structure, atthe top, for this purpose. 15

The portion of the sludge collected at sump 23 that is not required foractivation and re-seeding the aeration chambers, is pumped directly todi- 'gester The clariiled uid from secondary These ltrose plates larewell known articlesof commerce,` and they consist' of porous fusedescapes through them into the sewage, in finely divided bubbles.

In the arrangementsshown in Figs. 1 and 2, the compressed air conduitsare located at the bottom of the uter walls `of the aeration chambers,and air escaping from the ltrose plates is directed straight upwards. Inthis marmer the escaping air is enabled to impart to the sewage mass,atendency to rotate, in the manner indicated by when combined with thelongitudinaly gravitational flow that also is provided for, results incausing the sewage to flow helically through the length of the aerationchambers. This allows sufficienttime for the aerobic bacteria in the lsewage to function eicintly, to oxidize the organic matter therein, in amanner that is well understood. l

The helical ilow movement of. the sewage is important to secure, becausethe downward por- 55 The outflow from the re-aeration cham- 10V tion ofthe flow, indicated by arrow Il, tends-to carry some of the finelydivided air bubbles back down into the sewage mass. Such bubbles, havingto make the same circuit of now over again, obviously will remain incontact with the sewage much longer than they would if they werepermitted to break the surface thereof; and the longer the bubbles canbe retained in the sewage mass, the greater will be the eilect of thistreatment.

The natural buoyancy of the air bubbles in the sewage causes them totend to move upwardly,

with the same velocity at all points of the sewage l mass. At arrow Itit would be desirable to ret tard the circular velocitymfthe sewage,to'keep the bubbles in contact therewith longer. At arrow 38, on theother hand, 'it would be desirable to speed up the downward velocity ofthe sewage. to a degree considerably more than necessary to overcome thenatural upward velocityof the` air bubbles, so thatl the net effectwould be to retain the air bubbles in the 'sewage mass for at leastanother round of circulation. At arrow 31, it is desirable to quicklyaccelerate the cross-now of the sewage, to shorten the time duringwhichit 'would'be possible for the air bubbles to break the surface.. Atarrow l! the velocity of the circular ilow of theselwage should bedecelerated.

By the use of aeration chambers in the form oi' annular sectors, asillustrated in Figs. l and 2, I am able to fully realize the benefits ofthe principles just discusse Obviously the length lof theinner chamberwalls 4|- is much less than -which is theoretically most desirable.

The same results of circulation may be secured ,in the use of straightaeration chambers, if diagonally arranged cross walls 43 are employed,in the manner shown diagrammatically in plan in lFig. 3. In this casetheshort walls u correspond to the inner circular walls 4I of Figs. l

and 2; and the long walls 4l correspond to the Y outer circularwalls 42.The nltrose plates 3l are, of course,- arranged along side ofcthe long.

wallsofthetanks.

In, each of the arrangements shown, the sewage flows Yhelicallythroughfthe aeration chambers in the general direction indicated byarrpws 4t; suitable gates, or other iiow p being passing the sewage fromtank to ing chambers indicated in Figs. 1 and 2. will be found to beparticularly economical, both in construction and operation.` This isbecause of the,

smaller investment resulting from the more economical use of space; andbecause of greater convenience in operation. A sectorial control room l1is readily available by the use of such construction, and the compactarrangement re- 5 quires less piping, and shorter runs of pipe, thanordinarily are required. In such a control room, the necessary pumps.heaters, chlorinators, and

l blowers may be most conveniently located. The lighter apparatus, suchas the blowers, can be 10 very economically and satisfactorily installedon a mezzanine floor 4I in the control room.

Obviously, such a plant as that described, will require a considerableamount of auxiliary equipment. This has not beenillustrated or described15 herein, since it does not constitute any part of my invention. y

I claim:

' l. In combination; a clarifying chamber; a plurality of aerationchambers around the pe- 20 riphery of the clarifying chamber; and meansfor causing fluid contents of the aeration charnbers to circulate abouthorizontal lines intermediate their inner and outer peripheral walls;said aeration chambers being adapted for interconnection, aud fordischarging ultimately into said clarifying chamber.

2, In combination a circular clarifying charnber; a plurality ofoo-axial aeration chambers having the shape of annular sectors in plan,immediately outside .the clarifying chamber; and means for causing fluidcontents of the aeration chambers tocirculate about curved horizontallines intermediate their curved walls; said aeration chambers .beingadapted for interconnection, and having selective means for dischargingultimately into said clarifying chamber, in series or singly. I

3. In combination; a circular clarifying cham.- ber; a plurality ofcc-axial chambers having the so shape of annular sectors in plan,surrounding the clarifying chamber and making common use of itsperipheral wall; means for utilizingcertain of the last said chambersfor aeration chambers; means r causing fluid contents of the aeration 45to rotate about curved horizontal lines intermediate their curved walls;and means for selectively interconnecting said aeration chambers, andfor discharging their contents ultimately into said clarifying chamberin series or t0 4. In combination; a circular clarifying chamber; aplurality of co-axial aeration chambers having the .shape of annularsectors in'plan, im-

mediately outside the clarifying chamber; and

means located along the bottoms of the outer circular walls of saidaeration chambers, adjacent thereto. for blowing comminuted lairupwardly into nuid contentsl of said aeration chambers;

v said aeration chambers being adapted for intere0

